Write classes only once

[Rawi01]

This PR fixes mplushnikov/lombok-intellij-plugin#969.

In
https://github.com/eclipse/eclipse.jdt.core/blob/b3cc25e26a9b327ef6e79fbec3cde4d4fbeb60fc/org.eclipse.jdt.compiler.tool/src/org/eclipse/jdt/internal/compiler/tool/EclipseCompilerImpl.java#L444-L448
the stream gets closed twice. By wrapping the ByteArrayOutputStream in a FilterOutputStream the second close no longer perform any action.

@rzwitserloot After merging your latest Tycho changes I get a java.lang.IllegalArgumentException: argument type mismatch error. InteliJ does not print a full stacktrace so I do not know what exactly is broken.

[mplushnikov]

@rspilker @rzwitserloot Can you please merge this pr?

[rzwitserloot]

As I understand it, you're wrapping the BAOS in a FilterOutputStream because the impl of FOS has a volatile boolean-based system to ensure a close() call is only propagated to the wrapped OutputStream exactly once.

Unfortunately, a quick check of the JDK sources shows that this is not how FOS worked in java7. The volatile boolean was introduced somewhere between 7 and 14.

Given that we are still targeting some fairly old versions, I think we need to handroll this boolean. Shouldn't be a problem, it's still only like 5 lines of code. I'll set it up tonight, just informing you that the thing this PR intends to fix will be fixed, but not via this PR.

Anything I missed?

[Rawi01]

@rzwitserloot That's exactly why I wrapped it in a FilterOutputStream. I have not checked the older versions because the current comment described that behaviour and I thought that it behaves like that since Java 1...

[mkurz]

Any chance you update the edge release?
https://projectlombok.org/download-edge

[rzwitserloot]

@mkurz just released a new edge, with this fix.

[mkurz]

Thanks!